1. Technical Field
The present invention relates to an image forming apparatus.
2. Related Art
An image forming apparatus is already known that has liquid droplet jetting heads arrayed with plural nozzles, and employing liquid droplet jetting recording to form an image (including text) on a recording medium by relatively conveying the recording medium with respect to the liquid droplet jetting heads, and jetting liquid droplets, such as ink, from the nozzles towards the recording medium.
In such a liquid droplet recording-method image forming apparatus, since the nozzle faces of the liquid droplet jetting heads is brought into close proximity to the recording medium to jet the liquid droplets, sometimes, depending on the shape of the recording medium, the recording medium makes contact with the nozzles, resulting in dirt adhering to the recording medium, and/or causing scratching of the nozzle face, or generating other problems such as paper dust becoming clogged in the nozzles or irregular jetting.
To address such problems, an image forming apparatus described in Japanese Patent Application Laid-Open (JP-A) No. 2010-76872 includes an uplift amount detection unit that projects a beam of light along the width direction of the recording medium being conveyed by a conveying unit, and detects any uplift amount of a recording medium. When the uplift amount is detected to be a predetermined threshold value or greater, conveying of the recording medium is stopped, and/or the liquid droplet jetting heads are separated from the recording medium.
However, in the configuration of JP-A No. 2010-76872, when a temperature difference arises between the temperature at the periphery of the uplift amount detection unit and the temperature at the periphery of the liquid droplet jetting heads, resulting in a temperature gradient in the vertical direction with respect to the recording medium conveying direction, the light beam projected by the uplift amount detection unit is bent such that the light cannot be accurately received (the received light amount is attenuated) and an uplift amount is detected as being higher than the actual uplift amount. If, in such cases, the detected uplift amount is employed unaltered in determination of whether or not the uplift amount is a threshold value or greater, then sometimes a concern arises that conveying of the recording medium will be stopped or the liquid droplet jetting heads will be separated from the recording medium even though the actual uplift amount has not in fact exceeded the threshold value.